DOE-2 Engineers Manual Version 2.1A - DOE-2.com

CAPC2 is the design capacity of the double bundle chillers. Only CSOlAR
is deducted from the total cooling load in Eq. (V.I02b). Because of the
order in which the cooling load is allocated, HTDBUN would be zero if
CFREE or CABS were nonzero, hence, the double bundle would not be needed.
If CCOMP is smaller than CDBUN, CCOMP is reset to CDBUN.
The remainder of the cooling load is now allocated between the absorption
and compression machines. The allocation gives as much of the remaining
cooling load to the type, up to its maximum capacity, that makes the most efficient
use of source energy (compression chillers through an electric power
plant, or absorption chillers through a boiler), with any remainder going to
the other type.
The double bundle load is now separated from the conventional compression
chiller load. The program makes a check to insure that, if the double bundle
has been given a load, the load is large enough to prevent the double bundle
from false loading. No other load is given to the double bundle unless its
capacity is needed to meet the cooling load. The conventional compression
ch i 11 er is
CCOMP = CCOMP - CDBUN.
CCOMP at this point is now only the conventional compression chiller load.
Step 7.· Underloaded Equipment.
With the exception of the double bundle chiller, the program has not
checked to see if compression chillers are false loading or absorption
chillers are cycling on and off.
The program checks the conventional compression chiller load first. If
CCOMP is less than the minimum load, CAP1M, the program tries to give CCOMP to
the double bundle chillers, provided the double bundle chillers are turned on.
If the double bundle chillers do not have enough remaining capacity to handle
all of CCOMP, the program tries to shift part of the absorption chiller load
to CCOMP, provided the absorption chillers are turned on. If the amount needed
to be shifted to prevent the compression chillers from false loading is enough
to cause the absorption chillers to cycle, then the program tries to give all
of CCOMP to the absorption chillers. If this doesn't work, then conventional
compression chillers will have to false load.
The above is repeated for when the absorption chillers are cycling, except
that no attempt is made to give the absorption chiller load to the double
bundl e ch i 11 ers.
OPCOOl has apportioned the total cooling load to each type of chiller.
The routine lDIST is now called to allocate the load given to each type to the
particular sizes and number of each size of each chiller type.
V.l13